GEO Precise Orbit Determination Using Onboard GPS Carrier Phase Observations of Optical Data Relay Satellite

Takehiro Matsumoto, Takushi Sakamoto, Kazuhiro Yoshikawa, Sachiyo Kasho, Ayano Nakajima, Shinichi Nakamura

Abstract:	The optical data relay satellite (ODRS) is the first geostationary orbit (GEO) satellite that is equipped with the Global Positioning System Receiver (GPSR) for GEO developed by JAXA and NEC/NEC Space Technologies, Ltd. The use of GPS in GEO provides many advantages in satellite operation: enhanced position, velocity, and timing (PVT), reduced operating costs due to less dependence on ground station facilities, and autonomous orbit control for station keeping. In this paper, we present the result of the onboard data evaluation and precise orbit determination (POD) of ODRS using GPS L1 C/A code and carrier phase observations for 74 days. Despite the challenging receiving condition at GEO, the number of satellites tracked by the GPSR is 8.80 on average. As a result of POD, we found that both code and carrier phase observations are affected by the ionospheric delay when signals pass through the plasmasphere located above the ionosphere. To reduce the effect of the plasmasphere, we implemented four methods: set a higher cutoff altitude, apply correction sequences generated from orbit determination residuals, apply a new observation noise model depending on the GPS off-nadir angle, and use the GRAPHIC observations. Our results show that correction sequences and the new noise model improve the internal orbit consistency: the 3D RMS of overlap differences are reduced from 1.16-1.12 m to 0.76-0.74 m. On the other hand, the 3D RMS of overlap differences of the GRAPHIC orbit exceeds 3 m due to the large observation noise magnified by the code observations. We also found that the orbit bias in radial direction due to negatively biased carrier phase observations is mitigated from -51 cm to -17 cm by setting a higher cutoff altitude and applying correction sequences.
Published in:	Proceedings of the 35th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2022) September 19 - 23, 2022 Hyatt Regency Denver Denver, Colorado
Pages:	639 - 652
Cite this article:	Matsumoto, Takehiro, Sakamoto, Takushi, Yoshikawa, Kazuhiro, Kasho, Sachiyo, Nakajima, Ayano, Nakamura, Shinichi, "GEO Precise Orbit Determination Using Onboard GPS Carrier Phase Observations of Optical Data Relay Satellite," Proceedings of the 35th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2022), Denver, Colorado, September 2022, pp. 639-652. https://doi.org/10.33012/2022.18371
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